Microtubules are the constituent of

• spindle fibres, centrioles and cilia

• centrioles, spindle fibres and chromatin

• centrosome, nucleosomes and centrioles

• centrosome, nucleosomes and centrioles

A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. there is no formation of cell plate and thus the cell is containing more number of chromosomes as compares to other dividing cells. This would result in

• polyploidy

• somaclonal variation

• polyteny

• polyteny

3.

Which of the following is not a characteristic feature during mitosis in somatic cells?

• Disappearance of nucleolus

• Chromosome movement

• Synapsis

• Synapsis

Spindle fibres attach on to

• kinetochore of the chromosome

• centrosome of the chromosome

• kinetosome of the chromosome

• kinetosome of the chromosome

In meiosis crossing over is initiated at

• leptotene

• zygotene

• diplotene

• diplotene

The complex formed by a pair of synapsed homologous chromosomes is called

• equatorial plate

• kinetochore

• bivalent

• bivalent

Meiosis takes place in

• Meiocyte

• Conidia

• Gemmule

• Gemmule

The cell -mediated immunity inside the human body is carried out by

•  T- lymphocytes

• B - lymphocytes

• thrombocytes

• thrombocytes

A stage in cell division is shown in the figure. Select the answer which gives correct identification of the stage with its characteristics

• Telophase

  Nuclear envelope reforms, Golgi  complex reforms

  
  
  
  
  

• Late anaphase

  Chromosomes move away from equatorial plate, Golgi complex not present

• Cytokinesis

  Cell plate formed, Mitochondria distributed between  two daughter cells

• Cytokinesis

  Cell plate formed, Mitochondria distributed between  two daughter cells

Arrange the following events of meiosis in correct sequence:
(a) Crossing over
(b) Synapsis
(c) Terminalisation of chiasmata
(d) Disappearance of nucleolus

• (b), (a,) (d), (c)

• (b), (a) (c), (d)

• (a), (b) (c), (d)

• (a), (b) (c), (d)